I've searched and have been unable to find a solution to this problem. Actually its with my wife's phone, we both have Moments, mine works great but hers frequently (not all the time) doesn't shut off during phone calls. At first I thought she was just holding it strange but I have seen it for myself and its quite frustrating. The biggest issue is that its an intermittent problem so of course it never happens when at the Sprint store asking about replacing the phone. I did the recent update to the phone and it still does it. Any way to fix this short of getting a new one? Thanks!